The Ohio State University Herbarium (OS) is a major collection of plant and fungal specimens and is a unit of the Department of Evolution, Ecology and Organismal Biology. We are part of OSU's Museum of Biological Diversity. Since its founding in 1891, the collection has grown to approximately half a million specimens and has worldwide coverage, with strengths in flora of the northeastern United States (especially Ohio) and in temperate South America. The Herbarium supports research and teaching at OSU and receives frequent use by researchers from other academic institutions, as well as by staff from governmental agencies such as the Ohio Department of Natural Resources.
The collections continue to grow through contribution of specimens by faculty, students, and associated researchers, as well as by exchange with other herbaria. As they grow they increase in value as documentation of plant existence in space and time as a sample of natural variation, which facilitates our understanding of species boundaries, and as a source of phylogenetic data both morphological and molecular.